(1) Field of the Invention
The present invention relates to a fluorine-containing copolymer composition comprising a fluorine-containing copolymer and an organic silicon compound having an isocyanate group, and a fluorine-containing coating composition and a cured product thereof.
(2) Description of the Prior Art
A fluorine-containing copolymer is excellent in various properties such as weatherability, chemical resistance, water resistance, water repellancy and low frictional property, and therefore, application of this copolymer to a high-performance paint is expected. However since the fluorine-containing copolymer is insoluble or hardly soluble in a solvent at normal temperature, the copolymer cannot be used as a solution type paint or is poor in the adhesion to a material to be coated.
Japanese Examined Patent Publication No. 60-21676 teaches that a fluorine-containing copolymer obtained by copolymerizing four components, that is, a fluoro-olefin, cyclohexyl vinyl ether, an alkyl vinyl ether and a hydroxy-alkyl vinyl ether, is soluble in an organic solvent at normal temperature, a composition formed by incorporating a curing component into this copolymer is curable at normal temperature, and a coating formed from this paint composed mainly of this copolymer has the above-mentioned excellent characteristics of the fluorine-containing copolymer. However, in order to cure this copolymer at normal temperature, it is necessary to incorporate a melamine type curing agent or a urea resin type curing agent as the curing component, and the weatherability is accordingly degraded by incorporation of this curing agent.
We found that a fluorine-containing copolymer comprising a fluoro-olefin, a vinyl ether and a specific organic silicon compound is soluble in an organic solvent at normal temperature and this copolymer is cured at normal temperature without any aid of a curing agent other than a curing catalyst, and we already proposed this copolymer and a coating composition comprising this copolymer (see Japanese Unexamined Patent Publication No. 61-141713). However, it was found that this coating composition is insufficient in the adhesion to a film formed from an undercoating paint comprising an epoxy resin or the like.